Protective device



Inventor. Josef Biermanns, b3 f M HIS Attorney.

Patented Feb. 24, 1925.

UNITED STATES PATENT OFFICE.

J'OSEF BIERMANNS, OF KARLSHORST, GERMANY, ASSIGNOR TO GENERAL COMPANY, A CORPORATION OF NEW YORK.

ELECTRIC PROTECTIVE DEVICE.

Application filed Kay 11, 1923. Serial No, 638,426.

To all whom it may concern:

Be it known that I, Josnr BIERMANNS, a citizen of the German Realm, residing at Karlshorst, Germany, have invented certain new and useful Improvements in Protective Devices, of which the following is a specification.

My invention relates to protective devices and the protection of electric systems and more particularly to protective relays 0pative in response to abnormal circuit conditions with a discriminating time delay action which dependsupon the electrical conditions accompanying the abnormality. An object of my invention is to providean im proved relay responsive to abnormal circuit conditions such as over-current with a discriminating time action which is dependent upon the current and voltage conditions accompanying the abnormality in order selectively to control disturbed or faulty sections of an electric system without interrupting continuity of service on the remainder thereof. Another object of my invention is to provide an improved discrimr nating time limit relay which has a direotional action dependent upon an electrical condition accompanying an abnormality so that further discriminating action may be had in the protection of electric systems. A further object of my invention is to provide a relay whose time limit is substantial- 1 directly proportional to the voltage conition accompanying a disturbance throughout the operating range of the relay.

My invention will be better understood from the following description taken in connection with the accompanying drawing and its scope will be pointed out in the appended claims.

In the single figure of the accompanying drawing, I have illustrated an embodiment of my invention as applied to the control of suitable circuit controlling means, such as a circuit breaker 1 arranged to control the circuit of an electric power line 2 ex tending to a bus 3. While I have shown -for purposes of explanation, a protective device embodying my invention as applied to but one phase of the line, it is to be understood that one of these devices may be provided for each phase and also at different points of an electric system for sectionalized protection thereof.

The protective device illustrated comprises a current relay 4 operative in response to current above a predetermined Value in the line 2 to move one of a plurality of relatively movable members, such as cooperating circuit controlling members 5 and 6, in one direction at a speed dependent upon the current, and a relay 7 having a normally deenergized winding 8 arranged to be energized by line voltage upon the occurrence of line current above a predetermined value to move the member 6 relatively to the member 5 an amount dependent upon the voltage so that the members 5 and 6 may ongage each other after a, time which is a function of the current and voltage. The cnergization of the voltage winding 8 of the relay 7 may be effected by anysuitable over-current relay, although the relay -l which is herein shown as of the induction type, may comprise means for this purpose as will hereinafter be set forth. The relay 7 may also be a directional relay, as shown, operative in response to power in one dimotion to permit engagement of the men1- bers 5 and 6, and in response to power in 'the opposite direction to prevent engagement thereof, These members upon engagement may, for example, complete the control circuit 9 of suitable means, such as a trip coil 10 arranged to effect the opening of the circuit breaker 1, the control circuit 9 being connected to any suitable source such as a control bus, not shown.

For actuating the circuit controlling member 5, the relay 4 may comprise a rotatably mounted conductin member such as a disk 11, and for drivmg the disk in response to predetermined conditions, a motor element comprising a magnetic member or core 12 having a plurality of branches and a cooperating adjustably positioned magnetic member or armature 13 movable relatively to the core 12 in response to the energization, by current in excess of a predetermined value, of a winding 14 on one of the branches of the core 12. The winding 14 may be connected in series relation with the line 2 by a current transformer 15 and is normally energized. The relay 4 may also include a normally decncrgized winding 16 connected in series relation with the winding 14 across a preferably noninductivc resistance 17 also in series relation with the winding 1%. Normally the disk 11 is stationary but upon the occurrence of current above a predetermined value in the winding 14, the flux induced in the magnetic members 12 and 13 will result in the movement of the latter to the attracted position in which .the energization of coil 16 is effected by the closing of its circuit through relatively movable contacts 18 controlled by the armature 13. Upon the energization of winding 16, the disk 11 will be caused to rotate by reason of the fact that the winding 16 is connected across a non-inductive resistance in series with the winding 14. The flux in the central branch of the member 12 is therefore out of phase relatively to the flux in the outer branches and the disk 11 which is interposed between the magnetic member 12 and armature 13' will have a torque exerted thereon in a well known manner and will move across the magnetic field of members 12 and 13 when the latter is in the attracted position. The speed of the disk 11 is dependent upon the current and the relay 4 is preferably constructed to have an inverse time-current characteristic.

The circuit controlling member 5 may be mounted on a shaft 19 biased for movement in onedirection by suitable means such as a spring 20, movement in this direction being limited by a suitable stop 21. Suitable means'for increasing the time limit such as a reducing gear train comprising gears 22, 22' may be used to transmit the motion of the disk 11 to the shaft 19.

The relay 7 may also be of the induction disk type and is in certain cases preferably a directional relay. This relay may comprise a rotatably mounted conducting member such as a disk 23 arranged to be driven by a motor element comprising a magnetic,

member or core 24 having a plurality of branches and a cooperating magnetic member 25 between which the disk 23 is interposed so as to be movable across the magnetic field of members 24 and 25. The relay 7 may be arranged to be responsive to the direction of power in the line. In this case, the relay may include in addition to the voltage winding 8 a current winding 26. This winding may be connected in series relation with the line 2 through the current transformer 15 and also in series relation with the windings of the relay '4. The energization of the voltage winding 8 may be effected in response to predetermined current conditions by any suitable current relay or as shown by the armature 13 of relay 4. The armature 13 controls contacts 2'? arranged to complete the circuit of the winding 8 which is in shunt relation with the line 2 through a potential transformer 28 and comprises two coils which may be connected in series, as shown or in parallel to vary the sensitiveness of the voltage regulation. The lower of the contacts 18 and 27 may act as stops to limit the downward movement of the armature 13 to its attracted position.

The disk 23 is secured to a shaft 29 which carries the circuit controlling member 6 and which is biased for movement to a predetermined position by suitable means such as a spring 30 in a direction opposite the arrow shown on the disk. The shaft 29 may be colinear with the shaft 19 so as to provide a concentric mounting for the cooperating circuit controlling members 5 and 6. In order that the member 6 may be moved at a speed dependent upon the voltage, the coil 26 of the relay 7 is so proportioned that the central branch of core 24 is saturated at the minimum overcurrent condition for which operation is desired. Consequently the torque on the disk, due to the phase displacement of the fluxes induced in members 24 and 2.3 by windings 8 and 2G, is substantially proportional to the voltage and the amount of movement of the disk 23 is approximately directly proportional to the line voltage. Normally the relatively high inductance of the voltage winding 8 as compared with the current winding 26 is sufficient to provide a suitable phase displacement in the fluxes induced by these windings. This may be effected in other well known ways, however, as by inserting a highly inductive winding in series with winding 8.

In order to prevent engagement of the members 5 and 6 for a given direction of power, for example such as would rotate the disk 23 in a direction opposite that shown by the arrow thereon, suitable means such as a stop 31 is provided. This stop is normally down in the position shown and clear of the member 5 but the member 6 upon movement in a direction opposite that indicated by the arrow on disk 23 is arranged to raise the stop 31 into the path of movement of menr her 5. For this purpose, the stop 31 may be actuated by any suitable mechanism such as a crank 32 having an arm connected to the stop and another arm depending in the path of movement of the member 6.

Assuming the parts in position as shown in the drawing, the armature 13 will upon the occurrence of a predetermined current in the line 2 be drawn to the attracted position thereby completing the circuit of winding 16 of relay 4 and winding 8 of relay 7. Disk 11 will be rotated in the direction indicated by the arrow thereon thus effecting movement of member a in the direction indicated by the arrow on gear 22 at a speed which is dependent upon the current and which may be inversely proportional thereto. Upon energization of the coil 8, disk 23 will be rotated in the direction of the'arrow thereon at a speed substantially directly proportional to the line voltage. Consequently member 6 will be moved in the same .direction as member an amount dependent upon the line voltage so that member 5 will overtake member 6 to complete the control circuit of trip coil and thereby to effect interruption of the line 2 in a time which is approximately directly proportional to the voltage and inversely proportional to the current. Therefore, since an abnormal condition such as over-current due for exam le to a short circuit is accompanied by a rep in voltage from the source to the fault, it is obvious that, if the electric system is provided at different points with protective devicesembodying my invention, the devices will operate in a time dependent on both the current and the voltage. Since, however, the current is substantially the same at all points while the volta e decreases in proximity to the fault, the evices will function with a discriminating action, those adjacent the fault where the voltage is the least operating the quickest. Therefore the faulty line section or portion of the system will be disconnected without interrupting service on the sound portions of the system.

lVith certain electric systems such as rings and networks, it is preferable that relay 7 be of the directional type as shown in order to provide further selective or discriminating action dependent for example upon the direction of power. Assuming for example that the bus 3 is fed by more than one feeder 2, each provided with protective devices embodying my invention, then if a fault occurs on the feeder 2 between the source of power and the bus 3 power will flow from every source to the fault. Consequently the normal direction of power on the faulty feeder 2 adjacent bus .3 is reversed but not on the other feeders connected to the bus 3. Therefore it is desirable in order to maintain service on the sound feeders that the protective devices discriminate not only with respect to the voltage but also with respect to the direction of power. Thus for the fault condition assumed, the disk of relay 7 will be rotated in the direction of the arrow thereon and the members 5 and 6 will engage each other in a time dependent upon the current and voltage. In the'protcctive devices on the sound feeders adjacent bus 3, however, the disc 7 will be rotated in the opposite direction and member 6 will raise the stop 31 into the path of movement of member 5 thereby preventing the engagement of members 5 and 6 and consequently the disconnection of the feeders from the bus 3. Obviously upon the interruption of the portion. of the s stem at fault and the consequent return 0 normal conditions elsewhere on the system, the relays 4 and 7 will be deenergized and the springs and will return the members 5 and (l to their respective normal positions.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. A protective system for electric circuits of the type wherein circuit controlling means are arranged to be controlled by a pair of cooperating relatively movable contacts, comprising means for moving one of said contacts at a speed proportional tothe current in the circuit, power directional means for moving the other contact whereby with power flow in one direction said contacts may en age each other, and means controlled by sai power directional means for pre venting engagement of said contacts when the power flow in the circuit is in the other direction.

2. In a protective device for an electric circuit, a plurality of relatively movable cooperating circuit controlling members, a power directional relay comprising a voltage winding and a current winding substantially constant in effect for current above a predetermined value, operative to move one of said membeis in a direction dependent upon the direction of power in the circuit and at a speed proportional to the voltage of the circuit, a current relay operative to move another of said members in one direction at a s eed proportional to the current whereby with power in one direction said members may engage each other in a time dependent on the voltage and current, and means operative in response to power in the opposite direction to prevent the engagement of said members.

3. In a protective device for an electric circuit, a plurality of relatively movable members, a relay comprising a normally deenergized voltage winding operative upon energization thereof to move one of said members an amount dependent upon the voltage, and a current relay comprising means operative in response to current above a predetermined value to eflect the energization of said voltage winding and to move another of said members at aspeed dependent upon the current whereby engagement of said members is effected after a time approximately directly proportional to the voltage and inversely proportional to the current.

4:. In a protective device for an electric power line, a plurality of relatively movable cooperating circuit controlling members, a current relay operative in response to line current above a predetermined value to move one of said members in one direction, a directional relay having a normally deenergized voltage winding arranged to be energized in accordance with line voltage, said relay being operative upon energization of said winding to move another of said members, means arranged upon movement thereof in a direction opposite to the direction of movement of said one member to restrain the same a ainst movement, and means arranged to e ect energization of said winding upon the occurrence of line current above a predetermined value.

5. In a protective device for an electric circuit, a plurality of relatively movable cooperating circuit controlling members, a power directional relay comprising a normally deenergized voltage winding operative upon energization of said winding to move one of said members in a direction dependent upon the direction of power in the circuit, a current relay comprising means operative in response to current above a predetermined value to effect energization of said voltage winding and to move another of said members, and means operative upon movement in one direction of the member controlled by said directional relay to prevent engagement of said members.

6. In a protective device for an electric power line, a plurality of relatively movable cooperating circuit controlling members, a current relay operative in response to line current above a predetermined value to move one of said members at a speed dependent upon the current, and a relay having a normally deenergized voltage winding arranged to be energized in accordance with the linevoltage, said relay being operative upon energization of said winding to move another of said members an amount dependent on the line voltage whereby one of said members may overtake and engage the other in a time dependent upon the current and voltage of the line.

7. In a protective device for an electric circuit. a directional relay comprising a normally dcenergized voltage winding, :1 current relay comprising means operative in response to current above a predetermined value to eil'ect energization of said voltage winding and a circuit controlling member movable in response to current above a predetermined value at a speed which increases with the current, and a cooperating circuit controlling member movable by said directional relay upon energization of the voltage winding thereof in one direction to restrain the circuit controlling member associated with said over-current relay against movement and in the opposite direction an amount dependent upon the voltage whereby engagement of said circuit controlling members is effected after a time approximately inversely proportional to the current and directly proportional to the voltage.

8. In a protective device for an electric circuit, a plurality of relatively movable cooperating circuit controlling members, a

. current relay operative in response to current above a predetermined value to move one of said members at a speed dependent upon the current, a directional relay comprising a normally deenergized voltage winding operative upon energization of said windln to move another of said members in one irection an amount dependent upon the voltage whereby engagement of said members is effected after a time approximately directly proportional to the voltage and inversely proportional to the current and in the opposite direction to prevent cngagement of said members, and means operative in response to current above a predetermined value to effect the energization of said voltage winding.

9. In a protective device for an electric circuit, a magnetic member comprising a plurality of branches, a normally energized winding associated with one of said branches, a resistance in series with said winding, anormally deenergized winding associated with another of said branches and connected across said resistance, an armature adapted to be attracted by said magnetic member in response to current above a predetermined value in said normally ener ized winding to effect ener iza tion of said normally deenergized wine ing, and a member interposed between said magnetic member and said armature rotatable at a speed dependent upon the current when said armature is in the attracted )USlilOll.

10. The combination with an electric power line and circuit interrupting means therefor of means for controlling said interrupting means. comprising a plurality of relatively movable cooperating circuit controlling members, a current relay comprising a normally energized winding in series relation with said line, a normally deenergized wind ing ada ted to be connected in series relation Wit said line upon current above a pre determined value in said normally energized Winding, and means operative upon energization of both of said windings to move one of said members in one direction at a speed. dependent upon line current, and a relay comprising a normally deenergized voltage winding in shunt relation with said line, said relay being operative upon energization of said voltage winding to move another of said members in the opposite direction whereby to restrain said one member against movement.

11. The combination with an electric power line and circuit interrupting means therefor of means for controlling said interrupting means, comprising a plurality of relatively movable cooperating circuit controlling members, a current relay comprising a normally energized winding in series relation with said line, a normally deenergized winding adapted to be connected in series relation with said line upon current above a predetermined value in said normally energized winding, and means operative upon encrgization of both of said windings to move one of said members in one direction at 'a speed dependent upon line current, a relay comprising a normally deenergized voltage winding in shunt relation with said line, said rela being operative upon energization of said voltage winding to move another of said members in the same direction an amount dependent upon line voltage whereby said one of said members may overtake and enga e the other in a time dependent on line vo tage and line current.

12. The combination with an electric power line and circuit interrupting means therefor of means for controllm said interrupting means comprising a p urality of relatively movable cooperating circuit controllingimembers, a current relay having a winding in series relation with said line said relay being operative in response to current above a predetermined value to move one of said members in one direction at a speed dependent upon the current, a directional relay comprising a normally deenergized voltage winding in shunt relation to said line said relay being operative upon energization of said voltage winding to move another of said members at a speed dependent upon the line voltage and in a direction dependent upon the direction of power in the line, the amount of movement in one direction being dependent upon line voltage whereby upon the occurrence of a fault on the line with power in one direction engagement of said members is ctTcctcd in a time which is approximately directly proportional to line voltage and inversely proportional to line current, and means controlled by said directional relay operative upon the occurrence of a fault on the-line with power in the opposite direction to prevent engagement of said members.

In Witness whereof, I have hereunto set myhand this 23rd day of April, 1923.

J OSEF BIERMANNS.

Certificate of Correction.

Patent No. 1,527,623, granted February 24, 1925, to

JOSEF BIERMANNS.

It is hereby certified that error appears in the above-mentioned patent requiring correction as follows: The present drawing should be canceled and the drawing containing the figure as shown below should be inserted therefor as part of the Letters Patent:

Feb. 24. 1925. 1,527,623

J. BIERMANNS PROTECTIVE DEVICE Fixed May 11, 1925 Inventor: Josef Biermanns His Attorneg and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 1st day of March, A. D. 1927.

[IIAL] M. J. MOORE,

Acting Gems-sinner of Patents. 

